It is well known in the art that fresh roasted coffee gives off substantial amounts of carbon dioxide and other gases, particularly after roasting and grinding. In the past, after the roasting and grinding of the coffee, the roast and ground coffee is usually allowed to set for a period of time sufficient to allow substantial off gassing. The coffee is then placed into a package which is subjected to a vacuum packing operation. The vacuum packing process results in a low level of oxygen in the package head space which is beneficial as oxygen tends to stale the coffee product. Additionally, upon initial opening of the package an influx of air into the package results in an audible signal to the consumer that the product contained within it is fresh. A common package that is used to vacuum pack coffee is a cylindrical tin plated steel stock can. The can is easily opened with a common household can opener.
Recently, there has been a desire to package coffee immediately after roasting and grinding without substantial off gassing. Packaging of the coffee immediately after roasting and grinding provides substantial savings in the packaging of the coffee as the coffee does not need to sit in order to off gas. Furthermore, upon opening of a pressurized coffee package the consumer would receive a pleasurable burst of aroma of fresh ground coffee. This burst of aroma is much more noticeable in a pressurized coffee package than in a vacuum packed coffee package. The problem, however, with packaging particulate material, such as roast and ground coffee, under pressure is in containing the particulate material upon the initial opening of the package. For example if an ordinary coffee can was packed under pressure a significant amount of coffee material would begin to emit uncontrollably from the puncture in the can when it is initially opened with a can opener. This uncontrolled emission from the coffee can creates a considerable mess in the surrounding area that it was opened.
One package that is designed to contain particulate material, such as roast and ground coffee, while preventing the uncontrolled emission of coffee from the package upon opening is described in commonly assigned U.S. Pat. No. 4,966,780 issued to Hargraves et al. on Oct. 30, 1990. Hargraves discloses a semi rigid substantially gas impervious package for roast and ground coffee having a resealable closure. The package disclosed in this reference includes a means to prevent aspiration of the pressurized coffee from the discharge orifice of the container upon initial opening by the consumer. In a particularly preferred embodiment of the Hargraves package, the means comprises a porous filter member secured across either the discharge orifice or the resealable closure.
However, many consumers are so accustomed to the ordinary coffee can that they prefer it over other types of packages. Moreover, the ordinary coffee can provides for a significant cost savings over the Hargraves package. However, as stated above, when the typical coffee can is pressurized, the pressure causes the ground coffee to emit from the puncture in the can when it is opened using a normal can opener. There has, therefore, been a desire to provide a package for containing particulate material under pressure which is much like an ordinary coffee can and can be opened with common can opener, but which will prevent the uncontrolled emission of the coffee from the package upon initial opening.
It is, therefore, an object of the present invention to provide a package for containing particulate material under pressure but which will prevent the uncontrolled emission of particulate material upon initial opening.
It is another object of the present invention to provide such a package that can be opened with a common can opener.
It is another object of the present invention to provide such a package that appears to consumers to be an ordinary coffee can.
It is another object of the present invention to provide such a package for containing coffee to be packaged immediately after roasting and grinding and before substantial off gassing.
The aforementioned and other objects of the present invention will become more apparent hereinafter.